This invention relates to an improvement in a multiple sprocket wheel used for the change-over of a gear for bicycles and the like.
A conventional multiple sprocket wheel is arranged such that a chain guard and plural sprocket wheels of different diameter are separately manufactured, and assembled by use of a spacer and bolts or the like.
Where the chain guard and plural sprockets are separately manufactured in the aforementioned manner, this will require an assembly operation and necessitate the use of bolts and the like, thereby increasing the number of parts and rendering the production expensive.
In view of the above, it has recently been proposed that a chain guard of large diameter and a plurality of sprockets are punched out of a steel plate in such a manner, as to leave a plurality of connection segments, and that the chain guard and a plurality of sprockets are arranged in parallel with each other at predetermined intervals with a plurality of the connection segments bent, thereby obtaining a multiple sprocket wheel as a unit (for example, see Japanese Utility Model Publication No. 20475/82 and Japanese Patent Publication No. 26031/80).
With this arrangement of any number of sprocket wheels manufactured as a unit, a plurality of connection segments are, however, fabricated in such a manner that one or more teeth formed circumferentially of each sprocket are made unavailable. This arrangement is unsatisfactory when used in a sporting bicycle for hill-cycling because the chain may possibly be disengaged from the teeth of the sprockets thus requiring the chain guard to be mounted on the side of the sprockets of small diameter.